A Game of InchesSeptember 15 & 16, 2020
We’re in the middle of a ‘king tide’ cycle on the southeast coast, and the tides have been running roughly 1-1.5 feet higher than NOAA predictions (although almost exactly matching the NWS Advanced Hydrologic Prediction Service) in Charleston Harbor. The peaks of the high tides have occured during the evening the past two nights, which allowed me two opportunities to observe and document them. On 9/15, I biked around the Charleston Peninsula, and on 9/16, I remained on Lockwood Drive adjacent to the Ashley River through the peak of the tide.
The behavior of the tides seems to vary with each event, particularly due to the weather and the winds, and the peak tide observed at the Customs House appears to have occured 20 to 30 minutes after the predicted peak. The behavior of the tides also vary among the river systems, with the Ashley River peaking later than the Cooper River right now. The tides peaked at 8.09 and 7.92 feet MLLW on 9/15 and 9/16, respectively. While this may not seem like a substaintial difference (only 0.17-feet), the impacts along the developed land of the Peninsual are significant. Charleston really is a city at sea level, and these king tides show that it’s a game of inches as to the severity of the flooding from these tides. Thankfully, there was no significant rainfall around the peak of these tides.